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Last night I read about players with small hands who struggled with octaves. Then I looked to see if anyone made finger extensions. (??) .There is a Prosthetic site where they replace missing fingers so you can play the piano again. Just for a laugh I had a go at making an extension. First thought was to add something to the little finger. But the thumb is stronger and can reach both ways so the thumb was the best idea. I had a few strips of copper from a water pipe flattened out. 1/2 inch wide. An inch longer than my thumb. Two bits soldered on to stabilise the pressure on the keys. One under the thumb near the nail and one over to counteract rotation. The copper extended past the end about an inch and then twisted flat to line up with the keys.
Next stage. Some strips of gauze cloth coated with black silicone sealant to be used like a plaster of Paris structure . Fit on one rubber glove to begin with . Layers of siliconed cloth wound around the thumb before the copper piece was added then more cloth on top. The extended piece was buried in a thicker amount of sealant to take on the normal thumb thickness.
It`s the ugliest thing you ever saw as the surface is just like a buttered sausage roll. But Black! The part that meets the keys is the same width as my thumb. The copper part is well embedded so the keys are safe .Early fitting seems to be comfortable and I`m curious to see how it plays .The octave reach is fine .Without any wrist strap it seems to stay in place when I wag it around. (muffled laughter ). I`m 69 now and my right thumb joint is starting to hate me . As Henry Ford once said "Let`s crank it up and see why it won`t work ".

Second day . The "Thing" is dry now. It stays in place with no bother but flexing the first joint is a bit restricted. Seeing how stable the material is I shall make one without any copper and just use one layer of cloth. The end section could be lighter too with something hollow in place. The top ( and bottom ??) of the thumb joint can be left bare with material along the sides of the tumb. I noticed the thumb itself is narrower just where it joins the palm so it should be secure with a surrounding strip of siliconed cloth. The weight was the most noticeable drawback but the "new model" should be about 1/3rd the weight . The feeling on the key , I don`t think will be too much of a drawback. Think of gloves and shoes. There is an element of indirect feeling that could be absorbed into the system . One note about silicone sealant --It is easy to cut with a sharp knife and new material can be added and there it never comes unstuck . It is very friendly in that way .Also it is abrasion resistant . In a way it behaves like skin . There are more skin friendly moulding and flexible materials that could be used in place of silicone sealant . Edward Silicone Hands .

Day 3 . The reach with a longer thumb makes it seem remarkably easy . But the lack of feel plus me being a newish player is a double drawback. The lack of feeling could be improved with a looser fit at the tip to let the thumb have some feedback when contact is made. Just a fraction of an inch between thumb and false tip would be enough. The tip width does not need to be shaped like a real thumb at all . The index finger size would be better as the thumb size plus no feeling feels a bit clumsy . But mostly the playing seems to be improving in a new direction. One awkward chord before was really simple without any strain or reaching and twisting . I make a point of not looking at my fingers any more than I have to . I still want to keep that little discipline going . A fun project .

Isn't it more awkward to pass under a finger when playng scale passages? I would have thought that the altered ratio between the fist and second joint would feel a bit odd, since you haven't moved the knuckle.

Still, you're the one who's doing the playing; keep us posted how it's progressing.

I have to admit when I fist started reading this thread, my first alarmed reaction was "Robert Schumann!"

Hi Gizzy . The totally encased thumb felt uncomfortable so I cut out a section just about the width of the tumb to allow complete bending freedom. I needed to have a sesnse of contact when the end touched the key so I cut off the solid tip and slimmed that down a bit. Then I cut back the rest about 1/4 inch .The gap is now connected with one flexible layer of cloth . It`s simply coated with a thin layer of silicone and attached again. The new piece was glued outside the original so there is a small gap which allows some feeling if you gently touch anything. Before the thumb had a dead , numb feeling. Now I can sense if a small object is being held. The movement inside the tip is maybe 1/8th inch and then is quite firm but the "real thumb " tip can feel the difference .
If I hold my hands straight with all fingers vertical the left thumb edge nearly reaches my wedding ring. The false thumb tip reaches the pad of my small finger. I can alter the length either way to fit in with the pieces I`m learning.
ps. ( I removed all the embedded copper in a grisly operation. I might not make the grade as a surgeon . ) More Power Igor !

The thumb-- under aspect was sorted today. I cut another section off the inner soft part of the thumb where the hand creases. So there is an opening front and back . Then I added a thin piece to fit the second crease running up to the sides of the thumb joint. You see that kind of pivot in American Football where the knee is weakened. They fit a pivot both sides . The end of the black thing seemed to be pointing left too far for the notes I was playing so it`s been rotated to the right . One advantage with this compared to medical prosthetics is I don`t care what it looks like. It might finish like an insects claw. The notes were being played quite well without me watching the fingers but it`s useful to be able to do alterations. This game has some rules but I`m not sure what they are at present .

One of my friends when I was at university back in 1066 was the harpsichordist (well, he was an organist in those days) John Toll (the late) I now know someone who was a pupil of his, and he said that John had lost a thumb in an accident, and had a big toe removed and surgically sewn in the place where the thumb was
!!!!!

Gizzy I was just talking to a chap in the Diy shop yesterday about the Thumb and he mentioned a few wood machinists he knew that had two or three fingers missing. Then I remembered the toe being stitched onto a hand on tv . I wonder what the emotional shock must be to loose a finger .
The latest rolling modification was to sever the tip almost completely and turn it inwards a fraction. Thinking back I may have shifted it the wrong direction as the thumb mainly plays on it`s side. The reinforcement effect of an alteration makes the layer twice as thick too which looses that easy flexing I was using as a sensor . At the other end where the real thumb joins the palm , the loop running to the hinge joint sides of my real thumb is loose at present and it needs a separate extra loop straight around the real thumb to keep some stability. This arrangement may make the early section on top of the false thumb redundant. This is a very high speed type of evolution . What is the ideal situation for octaves or tenths ? Should the key nearest to the extremes be completely undisturbed or is a little touch without sound allowed ? I may need a little bump on the bottom surface to achieve that . You know what will happen. As soon as we can all play like Rachmaninov with his big hands they will compose more out -of - reach notes .

Butbutbut - Rachmaninov must have had more than just a long thumb. He must have had a good span betwen the fingers as well. There will be thngs in this big-hand music which can't be dealt with just by having one digit made longer? I work on my stretch (I can manage octaves but a 9th is really only possible if not much is going on in between the notes) by pushing thumb and little finger against the edge of the piano until they're almost in a straight line then of course giving it a shake-out.

Are you going to post us some picturea or better still a video of this bionic digit?

I can`t promise much on the photos but my son may be good at that . The combination of cloth and silicone is very useful as it has so much elastic memory but holds the basic shapes . It`s uncannily like real skin .Did I mention what material I use ? I don`t think so . It`s just a roll of decorating cloth that covers furniture when you paint the room . Beige coloured and very like open weave bandage. When you cut a strip the edges start to fray . At present I only have a tiny amount of the original construction still in place . The final form will probably be one loop around the thumb base .Connections to either side of the thumb joint then the tip enclosing the end just up past the nail. The side pieces flex to allow movement . If it`s kept thin it can fit closely. Two layers start becoming too solid.
Can you feel the rules developing ? None of this is tight against the hand as if it was an elastic band. I may use a wrist connection but hope it won`t need that . There is a cover for thumb bandages that has already been designed for that .

I`m getting down to the mechanics of this thumb extension now. The loop at the thumb base is extended along the sides with nothing above or below. That part needs to be firm enough to hold it`s shape. The flexing part needs to be kept level with the joint . At present the two connections to the "base loop" (See the terminology developing ? Next thing will be parts numbers ) are flexing too much. The addition to make a bump for key clearance (Key Clearance Bump ---KCB --- for those of us in the know ) has added some weight which needs looking at .Some looseness above the nail was cured by smearing a portion of sealant in the gap. Some changes can be made without the contraption fastened to my body , which is preferable . The gaps to help flexing also mean the thumb will not develop some dreadful variation of Trench Foot. Not a nice thought .
If anyone has a plaster cast of Rachmaninov`s hands it would be interesting to make an inside / outside glove adaptation when the groundwork is complete . If he wore a wedding ring it would add atouch of authenticity . I have realised that this thumb simulation is jumping in the deep end of the pool. I did that once before I could swim . It was interesting . The fingers have a much more straightforward action .

Just a few good alterations this time . The bump to avoid adjacent keys was sliced off and rotated to suit the actual angle the thumb presents to the key ,most of the time .The cutaway across the thumb pad ( the fingerprint area ) was too short so a layer was added for the pressing down action A general slackness around the nail top was cured by smearing a layer of silicone inside the false thumb. That was done separated from the hand and needs to be eased slightly but shows how the thicker (inner ) 1/8th inch silicone layer feels so secure and comfortable. Some neat silicone added to the outside of the side connections improved the springiness . This shows how it`s possible to balance a good fit with movement and security. I think adding thin stiffeners along the tip sides could make longer extensions work very well.
Extra interesting ,looking forward , is what would the ideal hand /fingertip layout be ? Splaying the fingers out , what pattern "should" be best ? Would all the tips in a straight line be best or a gentle even curve ? At present the false thumb and index finger lay level with each other . There was an article on the news today about photographing every type of Ant in a Museum collection so we could all look at the details of every variation . That`s the kind of wide ranging thinking an ant would use to develop a way to survive . Imagine Ants that played the piano . What would they recommend ? What shape would an Ant`s hand be ?
When Fritz Kreisler was old and his hearing failing he asked if the first note was in tune before playing some music. His muscle memory was sufficient to keep him on track . One or two fingers on a piano without 100 % feeling could be managed with good hearing . I know famous players often use their fingers to feel the key positions before playing them .

Doubling up today . The bump to clear the keys either side ( now giving 1/8th inch vertical clearance ) has been narrowed to fit the horizontal gap between the black notes. I tested my small finger between the group of 3 blacks but learned that that gap is a bit less than the gap between the pairs of blacks. I wonder why . I saw an article about the maths of that last week but did not take too much notice at the time .
The tip of the false thumb was rounded but it has too much tendency to slip off black keys so I added a blob of silicone to the contact area and lightly pressed it onto a patch of paper tissue to make it flat .The tissue will wash off easily later on . One point I enjoyed was how the slip off the black keys gave such a good grace note such as needed in the Gymnopedes pieces . That`s the material slip / friction rather than the shape . The narrowing of the tip between the blacks made for more movement in the tip so the top surface has 2 thin 1/4 inch wide cloth layers added . So 3 changes just there . It takes about 2 hours for the stuff to be useable so it`s not a difficult schedule. I don`t need a huge amount of patience before I see a result .
Getting near the final working shape the dimensions are as follows;
Loop around the base of thumb about 14mm width ,3mm to 5mm thickness (variable).
Side pieces (All one thing in reality ) 14 mm width about 5mm thick (variable )
Internal (real thumb )length 57mm.
Top of thumb covered 23mm (Nail top surface )
Bottom of thumb covered 29mm (Thumb print surface )
Nail surface (real thumb ) tilt from horizontal is roughly 30 degrees , giving a straight down (false thumb )contact .
Already the 2 top strips added ,are feeling stronger for the reinforcement .

The slimmer end works well but having the shape like a rubber hammer may be a drawback. I may try a longer reach with more of a normal finger shape later . Even with the one extension the fingering is far easier and the sound is well in line with the normal fingers . I shall look for a picture of Rach`s big paw . The thumb does not usually play between the black notes which is a good get out for that question .
The slimmer tip can be used for the other (??) fingers and the thin strips of reinforcement made a much bigger difference than I expected . I won`t try to build a bridge just yet though . All this draws attention to how clever the design of a real hand is .

Yesterday I cut a wine bottle cork in half and trimmed it thinner to make an extension shape for the small finger. The 3 middle fingers may be fine as they are. I won`t have so much lattitude to fit a loop around each finger. The thumb is a unique case . The friction and clutter rules out a repeat construction on each finger .
Holding the small finger extension in place is a puzzle to be solved.
The false thumb tip was not tilted far enough so it was severed and rotated some more. The small finger cast is in white and needs adjusting as it`s too loose. The last joint does not need much movement so may be covered by the flexible silicone . The wrist band idea may be necessary for a final layout .
Silicone seems too slippery for black keys so a different material layer at the tip is called for .
The thing is , I`m finding the notes and they all blend in nicely .

A sudden switch happened today . I started exploring a longer small finger too. That was amazingly easy. I just wrapped the silicone cloth around the cork and finger first. The first attempt starts loose. When dry the space can be taken up with 2 strips inserted above and below the finger. Start with cloth that has a thin coating and leave them to dry. Then add silicone on one side only so you can slide your finger inside ,but release after 5 minutes. Wind a layer of cling film round the finger first. It`s easy to release and let it dry in an hour. The white silicone dries quicker .That leaves a tube shape which is not quite right yet.
Cut off the end at 45 degrees and shape the cut off piece to angle downwards the way a joint would bend. Glue that back on again. The best length is just shorter than the ring finger . I was a bit ambitious with the thumb length and the cork idea would minimise too much flexing when pressing the keys. The false thumb tip was skidding off the blacks because it wanted to twist any way it could even though it seemed firm . That property needs some management. I shortened the thumb too. In fact without the thumb and just using the small finger one I can play a relaxed octave and find the notes better. There is a test comparing how often the other fingers are used compared to the small finger , so logically it`s better to extend the small finger . That`s a good new rule to remember .

I just used the small finger extension today . It feels less complicated although , overall , I much prefer bare fingers. It`s starting to annoy me even though progress is being made. The big danger with these addons is that a piece of music already learned will have to be altered in the fingers so I would separate the pieces used with the extensions. Also if you tried to practise scales it might mess up that too. It`s worth thinking about . The cork tip internal material is better as it`s so much lighter. I added a patch of canvas at the tip so I could use a different rubber layer .It would not have stuck to the silicone. Maybe some confusion arose when I swopped over from thumb to small finger. I will need to give it some days to settle down .The thumb , in a way , seems a more intelligent digit and coped better in the early trials. I wonder which finger is the cleverest .

None of it takes long . Longest time is letting it dry . All the materials are Cloth ,cork and silicone . One pair scissors ,a sharp knife and a spatula . I`ve got the basics now. The thumb can be made shorter . I may not have a lot of natural skill with this combination. Some people can draw pictures with an Etch a Sketch . Not me .

I think there`s still some mileage in these extensions. Comparing the small finger piece with the thumb , I have much less soft flexibility in the small one with thinner outer cover and cork. The thumb is very squashy and needs to be built around a plaster of Paris mould so I can use two hands . Now I know what shape to make it . The minimal extension of the small finger adds about 3/4 s the width of one key. Using both together I can reach a tenth . I should aim to be conservative at this stage . No sense being greedy .

I made a more accurate cast of my small finger in a black rubbery material that will not stick to silicone. I took longer than overnight to dry and will simplify new versions. It`s very creepy the way every detail of my fingerprint and nail is shown in black . The real fingertip with a curved tip is a better idea than a flattened shape . Any finger angle gives the same result , especially on narrow black keys ..

The small finger piece was made again with just one thin cloth layer and one side coated with a thin silicone layer. The tip was snipped to fold round the end without overlaps. A blob of silicone attached a shaped cork end in line with the normal finger and no hammer shape. (That hammer shape was a mistake. It`s progress to realise that ). The cork was sandpapered to match the normal fingertip shape. It flexed a bit when dry so I added a narrow strip of cloth all along the bottom of the finger . Not much more than 1/8th inch width . That is ample for pressing the keys. Inside the finger hollow I smeared a very thin layer of silicone near rhe open end to close a slight gap . Now it feels featherlight and more sensitive . I can sense when I am touching cloth without looking. The tiny "give "at the tip will be useful for quiet passages . There is a minute suction when removing the false finger . All the playing action tends to push it into position and falling off is never a problem . The top edge may like a stiffener for a Rolls Royce feeling . One annoyance with the casting of the finger was a tiny bit under the nail that I had to smear with silicone to smooth over . It was too small to see it inside . I cut my fingernail after the casting so the "bit " was pushing on the fleshy part under the nail . This is getting really detailed .

The normal fingers have a fingerprint area that is padded ,curved and lower than a straight out shape. All are worth copying . The small amount of flexing as pressure was applied was reduced by adding a kind of splint all along the top edge like a double thickness matchstick .I wound two pieces of linen thread around the ends to fix it still. Wood and silicone don`t glue very well. Then I realised that mechanically it would be better with just one loop around the centre instead of on the ends . I changed from linen to thin garden twine which is tough inert plastic . I made a loop in the twine ,not using a knot , but winding the twine continuously right round. Like the first stage of a knot but keep doing that all round and then finish the knot . The twine was then embedded in some silicone .Don`t forget the splint is an extension of the skeleton. All our hands would be wobbly like an octopus without a skeleton . The octave is well in reach with just this small finger extended . If you wore it all day , reading the paper and just getting used to it , I think it would become very easy. The pressure I can apply matches the middle finger now without any distortion . You need to wiggle it a bit to remove it. It does not want to fall off .

Some useful information comes from this experiment. The new stiffer , lighter version is very easy to fit. There is nothing like an elastic band around the small finger . It just fits very exactly . All the forces in use are pushing it onto the finger . if you flap the hand rapidly as if flicking water off the hand it stays perfectly secure. With the hand in a good piano position with fingers curved the original length felt too long and clumsy. I had made the extension an inch longer than my own finger. My small finger tip end comes level with the next finger joint. After I shaved some length of the false finger it was a tiny bit below the next finger . It sits on a table alongside the rest of the fingers in a more natural way . That natural feeling is the best way to progress . I think a whole inch is too much of a change all at once so I will use a similar construction for the thumb as the latest method holds in place so well . Then a compromise between the thumb and finger lengths can be worked out . The volume control of notes played was easy enough without any special effort. It is starting to indicate useful possibilities . In terms of finger strength versus thumb strength The thumb will have a more important role to play providing I stay away from the monster insect ideas .

I try to record all the impressions that occur as this progresses. It gives a better trace of the making process . Nothing was changed today but when I tried on the thumb extension after leaving it alone for a week it seemed very squashy compared to the small finger . The faults are glaringly obvious .I had no idea . It will be ten times better when I remake it . I suppose you call that iteration .

I have left the false finger alone for a while. As a beginner I needed to enjoy some more slow Chopin Mazurkas . Slow by me but making some delicious chords . The thumb may be the only addition necessary for the small extension I need for a comfortable octave . Bb below middle C is a busy note for a right hand and the small finger is not really interested in that . The higher Bbs are not a problem for the pinky . Maybe I need a false wrist .

I have to drag in a permanent part of this problem that has been hiding round the corner and sniggering. How can you feel the key with a lump of cork in the way ? Some kind of mechanism to let me know when contact was made ? A pivot would press down instead of up . So a double pivot (what`s that ?) might do the job. Or a pivot at the far end from the cork with a ring round the tip . A switch can be normally off or normally on. We need a both up and not a one up and a one down . If you follow me .

The real fingertip needs to feel the contact coming upwards onto the pad and not pushing against the nail . The pad shape was altered to remove the silicone layer touching the keys. it was too skiddy . The cork is closer to the grip of a fingertip . But , on removing the silicone the pad is not shaped enough to reach down into the keydip . Another piano forum sent an e mail today about their site and I`ve never been able to log onto it . They had a series of free videos about finger technique and one tip was to align the fingers near to the junction of the black and white keys ( ie away from the edge of the white keys ) to reduce stretching and keep a relaxed finger bend . That may help to make stretches easier , or less impossible .

An interesting diversion occurred on a violin site where a player has a thumb joint that collapses and makes holding the violin difficult. I recommended a splint made of --- siliconed cloth and a stiffener attached to his thumb just to restrict the backward abnormal movement . I advised him not to do any more Karate to avoid a painful future . If it works for him it will be a happy coincidence even if the piano version is not yet satisfactory . It was worth it just for that .

Sadly my attempt to design a thumb splint for the violin player caused an abusive sarcastic post from Australia that seemed at odds with my good intentions . The traditional splints look unbelievably clumsy .Double jointedness , (hypermobility) leads on to a lot of pain on later life . I tried to help .

The rather expensive alteration of a piano to fit narrower keys sounds appealing from a playing ,if not financial , angle. I had a nasty thought today . My "friend " , when I was about ten , told me to rub some live Poppy seeds on my hand . He said it would make a wart. Damn me it was true . How about inducing a finger extension with a wart ? What kind of friend gives advice like that ? I can still just see the trace of the circle on the base of my thumb .

Coming back to an idea after a gap shows the subconscious has been working at the problem by itself. It has just jogged my elbow and suggested a thinner end to the thumb regardless of the normal thumb shape. The splint construction using a small wooden stiffener showed a way to reduce the weight and flexing in the first efforts. Maybe an outer surface of felt could work well compared to anything rubbery. The dead effect of material at the key without feeling is less of a problem than I expected .The spatial ,angular ability of fingers seems to cope with that fairly well regardless .

Comparing my small-finger-to-thumb stretch today I noticed it was possible to match the left hand reach which was always 1/2 an inch greater. The trick is to pull the small finger upwards as well as outwards . If your palm is flat on the table the fingertip will come up an inch off the table. It feels awkward at first but it may be useful to try out . The top of the forearm muscles are being tensed for that alteration.

Looking at the way the thumb acts on a piano key you need the flex at the joint but something to counteract the sideways contact against the key. Some firm material below the tip and also above the second bone in the thumb . I`m sure the Gridiron Football designers have worked on this for metal knee joints . Carbon fibre looks like the favourite . If you`re rich .
In fact I read that gridiron football players are not protected by those knee joints and also that young players who are not fully developed are risking their health and legs . That has an echo of children damaging their hands on grand pianos.

Moving away from attaching stuff to my fingers I came across a very unusual idea for a keyboard layout .The Janko Keyboard .Plenty of information on Piano sites seemed to be a good answer. The octave is much narrower with that layout.But the penny soon dropped that you could not reduce the width without rebuilding the whole piano . I must have had a good day then because I sketched a very simple alternative to give a smaller reach.
Imagine an octave stretch which is just about 8mms too short ( mine ).That means each key needs to be 1mm narrower. Then when I reach for the octave it will be 8 mm closer . So each key needs something attached which will progressively overhang the previous note .Starting at middle C the next note up will have a 1mm bit sticking out left. OK so far? But the keys will need to drop ,when played , about one centimetre or more without hitting the overhang. So the new key surfaces have to be at least one centimetre above the original . Light plastic shapes such as extrusions (H shaped )can be cut and altered to suit the progressive difference in overhang. Just make pieces to fit the section away from the black keys for now. The i mm per key alteration divided into the original key width means the vertical part of the plastic component is still vertical when you arrive at about key 20 from the middle C. Some clever designing may be necessary to complete the set. But you see where I`m going. I only have a stretch problem with the smaller right hand but may at least cover the octave lower than middle C. If you have an old cheap piano you may like to use some glue rather than double sided tape.Weight can be adjusted for . It should be a good alternative to a £1,000 rebuild .

A drawback is imposed by the normal downwards movement of the key top.(about one centimetre).Once the overhang left covers one whole key width the the following one will start to overhang 2 keys.so the one centimetre rule is added on.That means after 20 notes the next batch has to be 2 centimetres above the original note tops . That will take care of all the notes above middle C and the reverse shapes below middle C.So the overall the new level has to be at least 2 centimetres higher than the original level . An interesting mathematical diversion to give a narrower keyboard.
Next problem ; How to get the lid shut!

The basic test is to mimic the position of 2 depressed keys one octave distance apart with a few strips of wood , each 1cm thick . Tape one to the table and adjust the other one . It`s surprising how much trouble a reduction of one mm per key can be.

A reduction of the octave reach which is 14cms down to 13.5cms seemed possible by taping 2 spatulas to the table.They have one centimetre thick handles.That stretch felt comfortable for an octave. The 14 cms is from the left edge of the D to the right edge of the B.That bridges 6 keys. The new width of each key will be reduced by [ 5 / 6 ] mms =0.83mms.
Each original key width is 22.5 mms
Dividing 22.5 by 0.83 gives 27. --for 27 increments of 0.83mm overhang per note .
The centre of my 7 octave piano is at the edge of E above middle C. 26 notes are above E .25 notes are below E.
So it all fits. Only a depth of one centimetre extra is needed .

Just to confirm the fit. All the right side notes are shifted left towards the E.All the bottom notes (left side) are shifted right towards the E.
From reading other forums about narrower keyboards this adjustment above would result in a 15/16th size keyboard. I wonder if that could become a Janko Keyboard as well ? There was a question about fingers fitting between the black keys. So apart from the style that we have always seen is there any reason why the sides of the black keys are bevelled outwards at the bottom ? The gap is 2mms less at the bottom. I only wanted 5mms less for a whole octave. Interesting question. While we`re at it , the black keys when depressed are still above the white key surface .There may even be a reason for that . ( It`s a tactile aid when playing apparently ).

Yes the length of the key gives it a good chance .The most extreme overhangs are at the outer ends of the keyboard . What would a numbered or lettered set of plastic shapes cost ? Not a lot. Most of the central keys will have the vertical section of each piece right below the finger so there will be no force to lift it off or push it sideways .
I read one comment from a student who used a biro cap stuck on his small finger to play a chord in an examination .
Recipe ingredients ; One length of H shaped plastic extrusion --to be cut and adjusted .
Width of extrusion 5 mms to allow (after cutting ) -centre (vertical bit ) to edge of 2 .25mms
Depth of extrusion 10 mms (internal gap add a bit for safety) plus thickness of plastic (2 layers --top and bottom ). Maybe 14 mms total.
One fine saw .One ruler. One sanding disc.
Length of attachments helps stiffness and security and hinders weight on keys.
Check down weights and up weights.
Half way from the centre note E the vertical section of plastic can still be under the middle of the attachment. That works left and right , so half the whole keyboard ,which is the middle and most used , will be quite reliable and secure .
Sticky tape is a worry before you put it on ,in case it comes off. When it`s in place the worry is whether it can ever be shifted again .

I came across a site that specialises in skin safe silicone called "Renew" .It supplies materials for fitting prosthetic limbs. The picture of an amputee`s leg with the silicone flexible moulding around the knee made me think it was a finger with an extension. There may be lots of sites that could help with making a bigger stretch on a piano .

The best solution to a short hand span seems to have emerged for me . The Korg Microkeys with 61 keys is a midi controller that can be combined with the Pianoteq system to keep me happy for a while. The Korg has no speakers of it`s own and costs less than £100 new .The microkeys are not as tiny as they sound . Effectively the octave will be about one inch shorter. "Ah, Parfait" as they say in France. Serious teachers will frown to know that I will not suffer the pain and anguish of struggling with full sized keys . Not "No Pain , no Gain". Just "No Pain". Ha Ha .
However I had a lingering fantasy yesterday for an old Bluthner medium sized Grand Piano on e bay for a princely sum of 99p. The renovation of such a masterpiece would only cost about £19,000 . Of course it would need some tuning on top of that . But the Bluthner sound is there on Pianoteq for not a lot a of pennies .Ha Ha Ha .

A new cloud on the horizon . What would your average player with small hands do if they could get a keyboard with smaller keys ? Starter for ten points and no conferring .What composer would they look towards ? One with big hands ? Like Rachmaninov for instance? Got it in one. And what particular piece would they have in mind ? Could it be perhaps a very popular prelude in C# sharp minor ? His most popular solo composition ? Well don`t get your hopes up with a Pianoteq setup because the high and low notes in that music are just outside the 61 note range. Somebody up there must hate us .
Since this is a Frankenstein topic I have just been cutting off the fingers and thumbs from a pair of plastic gloves for some plastering jobs in the house. I always find the gloves too big and they drag in the smooth plaster just when I don`t want . So then I reglued them with an overlap to fit my short fingers .I just do my best and struggle against all odds .

My friend was tuning for an internationally famous diminutive exponent of Rachmaninov and asked how they coped with the huge stretches required.
'I cheat,' they replied. So now that's what I do too... Different sized keys would only cause confusion.

I have just been looking at the images for Prosthetic hands made by professionals and amateurs , and also children as their school projects.
Although I have tried to keep a light hearted feel about the piano finger/thumb topic there is still some serious ,useful stuff that might come out of this .
The appearance should not be the most important concern if the function is to be achieved . I realised that fitting anything too near the fingertips causes instability and wobble. So moving back towards the wrist looks more hopeful . I am visualising firstly a wrist strap (leather or plastic ) to make use of the wrist becoming wider as you get closer to the fingers.That will prevent slipping off .Then a section around the hand . Ie under the palm and across the back of the hand . That will be all one unit with the wrist strap. The palm section will not allow the thing to rotate out of place as if it was a wristwatch .None of this will be tight or interfere with fingers or thumb.
The purpose of the above fitting is to create one stable ,and flexible ,attachment place for the small finger extension. That will be a curve of plastic flexibly attached to the back of the hand piece and curving forward over the small finger . The small finger will fit inside a slot to control the extension fingertip. Up and down movement and side to side movement will be allowed by the flexible fitting at the other end .
Position of the flexible fitting will be on a line from the thumb web to the right side wrist joint. Then draw a line back along the small finger to meet the hand crossing line. Mechanically that seems fairly secure and straightforward .
Not being a very expert player I have to ask for some guidance here about the small finger movements . Is the forward and backwards ability of the small finger used much for playing black and then white notes ?